The aging spec on the 10811 is 5 parts in 10^10 per day.
After 60 days, it could be off 30 ppb. So what we
have here is a non-ovenized AT cut that is better
than an ovenized SC cut. I'm sure.
I am reminded of the old Accutron ads. The headlines
guaranteed so many seconds a day or whatever it was.
The fine print says they don't actually guarantee that.
The only remedy under that guarantee is that they
agree to adjust the watch to be in spec at the
watch repair shop and hand it back to you. Thus,
they didn't have to worry about aging. Just come
into the shop as often as necessary :-)
Rick N6RK
On 4/11/2018 9:26 AM, tn...@joshreply.com wrote:
That comes out to about 30ppb, and this is a pocket watch so they dont seem
to depend on the temp stabilization of being attached to a human wrist.
https://www.ablogtowatch.com/wp-content/uploads/2018/03/Citizen-Cal-0100-Eco
-Drive-Movement-04.jpg
Ive been reading about the new watch that contains this crystal for about a
month, but just saw some more detail today
---
AT-CUT QUARTZ CRYSTAL OSCILLATOR
While AT-cut quartz crystals have indeed been in production and use since as
early as 1934, the technology is more common in larger applications and not
necessarily wristwatches. To address the needs of individuals seeking only
the most accurate performance in a wristwatch, Citizen sought to apply and
optimize this available technology in a way that could serve watch consumers
on a more direct and personal level. When working to reach the accuracy of
the Cal.0100, Citizen opted for an AT-cut quartz oscillator instead of a
more traditional tuning fork shape (XY cut). Perhaps most notably, AT-cut
variations allow for greater temperature tolerances, specifically in the
range of -40°C to +125°C. Additionally, this configuration allows for
reduced deviations caused by wearer orientation, which can cause significant
changes in accuracy that aren't negligible when attempting this kind of
performance. As a result, wearers will not have to worry about errors caused
by spatial orientation and positioning becomes less of a concern. The same
can be said about durability, which Citizen also improved upon in
conjunction with the AT-cut oscillator. After all, shock experienced in
day-to-day situations could easily prove detrimental even for quartz
movements. And when the goal is an annual accuracy of ±1 second, that just
isn't acceptable.
https://www.ablogtowatch.com/citizen-cal-0100-eco-drive-watch-movement/
---
Is this possible with an MXCO running across this wide temp range? How are
they compensating for aging at this level of precision?
Thanks!
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